The effect of passive film on mechanical properties of the martensitic stainless steel 15-5PH in neutral 3.5 wt% NaCl solution was investigated, using surface analysis techniques, electrochemical measurements and slow strain rate technique. In neutral 3.5 wt% NaCl solution, the passive film formed at passivity potential is mainly divided into iron oxides-rich outer layer (FeO, Fe2O3) and chromium oxides-rich inner layer (Cr2O3, Cr(OH)(3)). During crack propagation, the passive film reduced formation of micro-cracks and micro-cleavages around the crack tip, and as a consequence, remarkably increased the fracture ductility of the martensitic stainless steel. (C) 2014 Elsevier B.V. All rights reserved.